EXPERIMENTAL STUDY OF ADIABATIC COOLING EFFECTIVENESS ON AN EFFUSION COOLED TEST PLATE WITH MACHINED RING GEOMETRIES

The present study deals with experimental investigation of adiabatic cooling effectiveness on an effusion cooled test plate with machined ring geometries. Initial tests were performed on an effusion cooling holes. The cooling effectiveness at the beginning of effusion holes is lower, and it increases in the flow direction mainly due to the additive effect of film cooling effectiveness of the effusion cooling geometry. Subsequent tests were done with machined ring geometries fixed ahead of effusion cooling hole geometry to improve the cooling effectiveness before the beginning of effusion cooling holes. These machined ring geometries act as a wall jet and reduce the hot side heat load by film cooling performance. Tests were performed at a coolant to mainstream density ratio of 1.3 and at blowing ratios ranging from 0.5 to 2.5. Increase in the blowing ratio shows an increase in the cooling effectiveness. Comparison results show that the adiabatic cooling effectiveness increases significantly before the effusion cooling holes in the presence of machined ring geometries at all blowing ratios.